After 6 months, 7.3% of smokers using the e-cigarette were abstinent compared with 5.8% of those using the patch and 4.1% using a placebo e-cigarette without nicotine, Christopher Bullen, MBChB, MPH, PhD, from the University of Auckland in New Zealand, and colleagues reported in The Lancet.

Due to the lower than anticipated achievement of abstinence, statistical power was insufficient to conclude the superiority of nicotine e-cigarettes. However, a post-hoc analysis showed established e-cigarettes were noninferior to the patch.

The trial included 657 adult smokers who wanted to quit. Participants were randomized to at-will use of nicotine e-cigarettes (16 mg, N=289), a daily nicotine patch (21 mg, N=295) and placebo e-cigarettes (N=73). Use was initiated one week before and continued 12 weeks after participants' quit day. The primary endpoint was 6-month biochemically-verified abstinence.

There was a 1.51 percentage point difference in 6-month abstinence rates among nicotine e-cigarette users and patch users, which was not significant (95% CI:-2.49-5.51). The difference between the nicotine-dispensing e-cigarettes and placebo was slightly wider at 3.16 percentage points, but still not statistically significant (95% CI:-2.29-8.61).

However, nicotine-dispensing e-cigarettes did help participants cut down on the amount they smoked -- reducing mean consumption two cigarettes per day more than the patch (P=0.002). At 6 months, the proportion of e-cigarette users who at least halved the number of cigarettes smoked was 57% compared with 41% of patch users (P=0.0002).

Relapses also occurred later at a median 35 days compared with 14 days with the patch (P<0.0001) and 12 with placebo (P=0·09), the researchers found. Adverse events were generally not serious and did not differ from those associated with the patch (incidence rate ratio 1.05, P=0.7).

All participants were provided with a quitline for telephone counseling and text message support, put only 36% to 40% across the groups used this option.

In an accompanying editorial, Peter Hajek, PhD, CClinPsych, of the UK Centre for Tobacco and Alcohol Studies at Queen Mary University in London, noted several other advantages of e-cigarettes over other nicotine replacement therapies.

Because e-cigarettes are regulated as tobacco rather than medication in the United States and most other countries, smokers have easier access without the need to visit a healthcare provider, he pointed out.

"[S]top-smoking services which distribute nicotine replacement therapy with minimum support now have a cheaper alternative to consider, and health professionals will now hopefully feel easier about recommending e-cigarettes to smokers, or at least condoning their use," Hajek wrote.

Another "untapped potential of e-cigarettes" could be a lower risk for lung cancer due to fewer carcinogens than with smoked tobacco among long-term e-cigarette users. However, concerns remain that e-cigarettes may renormalize smoking, he added.

Long-term e-cigarette use requires more researcher, the researchers emphasized. Limitations to the current study include higher loss to follow-up and withdrawal rates in the patch group, and use of earlier generation e-cigarettes, which have lower nicotine delivery compared with tobacco cigarettes.

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